A warewashing machine is a utility dishwasher used in many restaurants, healthcare facilities and other locations to efficiently clean and sanitize cooking and eating articles, such as, dishes, pots, pans, utensils and other cooking equipment. Articles are placed on a rack and provided to a washing chamber of the warewashing machine. In the chamber, rinse agents, e.g., water, and cleaning products, e.g., chemical solutions containing detergents and soaps, are applied to the articles over a predefined period of time referred to as a “wash cycle.” A wash cycle includes a cleaning cycle and a rinsing cycle. At least one cleaning product is applied to the articles during the cleaning cycle. At least one rinse agent is applied to the articles during the rinsing cycle. The article racks contain holes that enable the chemical product and rinse agent to pass through racks during the cleaning and rinsing cycles, respectively. At the end of the wash cycle, the rack is removed from the washing chamber so that other racks carrying other articles may be moved into the washing chamber. The wash cycle is then repeated for each of these subsequent racks. Wash cycles may be customized for specific types of racks and the articles that the racks carry.
The cleaning products applied to the articles by the warewashing machine are formed and contained in a solution tank typically located on the underside of the warewashing machine. A wash module is provided above the solution tank and in the lower portion of the washing chamber. The wash module extracts a cleaning product from the tank and applies the cleaning product to the articles contained in the rack during the cleaning cycle. Following the cleaning cycle, a rinse module, which is provided in the upper portion of the washing chamber, administers the rinsing cycle by applying a rinse agent to the articles thereby rinsing the cleaning product from the articles.
Conductivity of the cleaning products used by warewashing machines to clean and sanitize articles used in public facilities is governed by various food and health regulations. Conductivity is defined herein as a percent relation of chemical products forming a particular cleaning product. The term chemical product is used broadly to encompass, without limitation, any type of detergent, soap and rinse agent, including water. To meet these regulations, a conventional warewashing machine typically utilizes conductivity cells to sense conductivity of a cleaning product situated in the solution tank of the machine. This sensed information is provided to a controller overseeing operations of the warewashing machine. The controller uses this sensed information to determine the percent concentration of each chemical product forming the cleaning product. If the percent concentration of a particular chemical product is below a range prescribed by the governing regulations, the controller controls dispensing of an appropriate volume of that chemical product needed to force the conductivity of the cleaning product to the prescribed range.
As noted in the previous paragraph, conductivity cells provide a manner in which conductivity of a cleaning product can be controlled to meet certain regulations. However, these cells may yield inaccurate results or be altogether inoperable. For this reason, field persons responsible for operations of a warewashing machine are still required to periodically visit the machine to titrate the cleaning product used by the machine. The act of titrating a cleaning product refers to measuring conductivity of the cleaning product, and more particular, measuring a percent concentration of one or more chemical products forming the cleaning product.
In titrating a cleaning product, a field person first activates the warewashing machine to start a set of sequential wash cycles. Next, after waiting a predetermined period of time, the field person extracts a sample of the cleaning product from the solution tank. Then, using a conventional titration test kit, the field person estimates the conductivity of the cleaning product by applying one or more test chemicals to the sample and monitoring changes in the sample.
During sequential wash cycles, at least one chemical product and a rinse agent are added to the solution tank on demand thereby rendering continuous changes in the conductivity level of the cleaning product. That is, the percent concentration of the chemical product relative to the cleaning product varies as both chemical product and rinse agent are added to the solution tank. Depending on whether the field person extracts the cleaning product sample following dispensing of the rinse agent or the chemical product, the results of the titration may lack precision with respect to one another, thereby rendering the titration test relatively inaccurate. As such, the field person is required to estimate satisfactory times for titrating a cleaning product. The results of such titration tests therefore depend on how well the field person estimates such times and whether the warewashing machine is actually operating in a manner foreseeable by the field person when making the estimates. For at least these reasons, current titration techniques used by field persons are somewhat unreliable for ensuring that the cleaning products used by warewashing machines meet the various governing regulations.